Planet Venus: Earth's 'evil twin'

By Paul Rincon
BBC News science reporter

The Babylonians called it "Ishtar". To the Mayans, it was known as "Chak ek", which translates as "great star".

Some ancient astronomers believed it was two separate objects: a "morning star" and an "evening star".

Venus is the brightest object in the sky except for the Sun and Moon. As such, the second planet from the Sun has fascinated humankind for millennia.

Europe's Venus Express spacecraft blasts off this week, and will rendezvous with our nearest planetary neighbour next year to study it from orbit.

The mission aims to shed light on an enduring mystery about this world: how a planet so similar to our own in size, mass, and composition has evolved so differently over the last 4.6 billion years.
http://news.bbc.co.uk/1/hi/sci/tech/4335628.stm

..Earth at one time...Beautiful Oceans, Rich-Green Forests, Bountiful Lands.
And then the Republicans came along.. :)

Now just a burnt out shell...

geez, I never knew.

I mean, similar though it may be in size, mass and composition, it is not identical.

For one, it is closer to the sun. It seems to me that the mystery would stop right there, but hey, just for kicks, let's continue...

Ecosystems (in this case, the entire planet) are extremely fragile. One tiny, seemingly insignificant thing changes and the entire system changes.

It stands to reason, then, then the slightest variations in size, mass, composition, galactic location, etc, would ultimately manifest in gross overall differences between planets.

But hey, that's just me. ;-)

but it is an example of greenhouse gases run amok. The atmosphere is largely CO₂, and has ninety times the atmospheric pressure of earth, resulting in a temperature hundreds of degrees above what it would be with an atmosphere like earth. THAT is a message for anyone who thinks greenhouse gases are a non-issue.

We've seen so many pictures of the Martian surface, but because Venus was explored by the Soviets, you never seem to the pics taken on the surface of Venus:

...several billion years ago, Venus probably had oceans, plate tectonics, and life. Like Earth, it was kept at a reasoable temperature by a constant draw down of carbon dioxide by erosion as the Sun slowly increased in brightness since it's birth (as a result of the core getting denser as H is turned into He). When all the CO2 was taken from the atmosphere, there was nothing keeping the ever brighting sun at bay, as Venus warmed, more water evaporated into the atmosphere, and since water vapor is a greenhouse gas, a vicious cycle resulted, the oceans boiled away, The water vaopr made the planet so hot that the limestone rocks that stowed away CO2 for eons broke down into CO2 and calcium oxide. finally, all the water vapoer was distroyed by UV light, leaving Venus the Hell it is today. Plate tectonics stoped working when the oceans boiled away because subduction required the subducting rocks be hydrated. Venus became the Hell it is today. Earth will suffer a similar fate 2 billion years from now.